As the sport of triathlon gained in popularity Scott turned pro in 1983. Between those early years and his move back to the amateur ranks in 1999, Tinley competed in over 400 triathlons, winning close to 100 of them, making him one of the top three winning triathletes of all time.

He won the Ironman World Championship twice (1982, 1985) and the Ironman World Series three times. He was inducted into both the Triathlon and Ironman Hall of Fame upon retirement in 1999.

Near the end of his professional career he helped found and develop the sport of offroad triathlon and continues to co-own and manage the longest running offroad triathlon in the world, Scott Tinley’s Adventures in San Luis Obispo, California.